There has been considerable attention given to the ethical, legal and social ramifications of possible approaches to screening for genetic traits which may predispose particular individuals to the deleterious effects of exogenous chemical exposure. There has, however, been little comparable assessment of the state of the scientific basis for this sort of trait identification. The emphasis of this conference will be on assessing the current scientific base for detection and characterization of such genetic markers. Particular genetic and biochemical markers together with their import when placed in conjunction with specific environmental or occupational exposure to genotoxic agents will form the major focus of the conference. Enzyme systems relevant to the human activation and detoxification of xenobiotics, DNA repair capabilities, immunological markers and their molecular probes, identification of human oncogenes, population studies and correlative approaches derived from pharmacogenetics will comprise major sections of the meeting. The discussion sessions, which may be anticipated to be particularly revealing in assessing existing capabilities and potential developments in these areas will be transcribed and included along with the formal presentations in the publication of the meeting procedures. Following prior Banbury Center practice, publication is anticipated within seven months of the meeting date.